design - How to write a Java class following the SRP principle ? My specific case study -

i doing small project/exercise in among other things have create html parser evaluate server-side script, give values variables in -${ ... } - , that´s all.

to achieve have written single class called "parser" have 1 public method "parsehtml()" , couple of private methods hard work. issue comes when think 1 of 5 s.o.l.i.d principles: srp = class should have 1 reason change:

i got not idea how structure class having know private methods called inside public one. kind of facade pattern made method.

+ public parsehtml() - private getexpressionsfromhtml() //method grab ${..} file - private evaluatejavascript(script) - private deletejssnippetfromhtml() - private setvaluestoexpressionsinhtml() - private evaluatedataif()  - private evaluatedatafor() 

here there link author explain principle of single responsability well... still got doubts it:

http://www.codeproject.com/articles/567768/object-oriented-design-principles

so, missing in this?

when write code, tend code following these sort of design: define related methods single actor going use, , sort of interface/public method deal of mini private methods. keep them sort can a.k.a less 20? lines per method, 1 or 2 lines.

as can see above method´s names descriptive possible avoid write unnecessary comments.

regards

edit

the aim of application given "index.html" able to: * read file * process javascript in .html - javascript engine - rhino * parser final html render in browser.

a servlet take program , render "parsed file" in browser. servlet looks ...

protected void doget(httpservletrequest request, httpservletresponse     response) throws servletexception, ioexception {      string path = request.getservletcontext().getrealpath("index.html") ;      parser parser = new parser();     string screen = parser.doparsehtmlfile(path);         printwriter out = response.getwriter();          out.println(screen); // rendering page, ok this? } 

now list classes makes parse possible. record, parse entirely done using regular expressions, have heard many times not appropiate html due nested tags guess little project/exercise work:

1. parser.java

   public string doparsehtmlfile(string filename) { /*not sure if method extract class called instance: proccesshtml.  looks me facade class?*/      // readfile      read.readfile(filename);     this.htmlparsed = read.gethtmlfile();      // processserverside     this.attributesmap = processor.processserverside(this.htmlparsed, read.getscriptsnippet());      // parsehtml     parsehtml();      return this.htmlparsed; }   private void parsehtml() { /*this method 1 keeping responsability in class of formatting htmlparsed variable*/ if( !htmlparsed.isempty() && !attributesmap.isempty() ) {     this.removejsfromhtml();      this.setvaluestoexpressionsinhtml();     this.evaluatedataif();     this.evaluatedatafor(); } 

   }

2. processor.java

   • public map processserverside(string file, string script) // method uses list of private below - facade ?
   • private scriptengine processjavascript(string script)
   • private void getdataattributes(string file)
   • private void evaluatedataattributes(scriptengine engine)

   all private methods relies on each other. attributes going evaluate if don´t call first 'getdataattributes'???

3. reader.java

   • public void readfile(string filepath)
   • public string getscriptsnippet() // javascript section
   • public string gethtmlfile() // whole html